Hi, Arleen --
Thanks for writing to T2T. My best recommendation is to read what the
National Council of Teachers of Mathematics (NCTM) says in their Principles
and Standards for School Mathematics. If your school does not have a copy,
you can get free 120-day access to it online at
http://standards.nctm.org/
Go to the Algebra Standard for Grades 3-5 (pp 158-163 in the book version).
NCTM has an excellent book in their Navigations series on teaching algebra in
grades 3-5. It has some good general discussion of the topic and rationale
for the teacher as well as specific activities you can use with your class.
When we talk about teaching algebra in the elementary grades, we don't mean
manipulating equations with variables, as is taught in a high school algebra
class. It has more to do with patterns and thinking about relationships. Are
you familiar with function (in/out) machines?
The best way to start is with a word problem that gives students a context
for algebraic thinking and a way to judge whether their results make sense.
You can get a free 21-day trial account to our Problems of the Week.
http://mathforum.org/products/trial.html
In the Math Fundamentals Library under Algebraic Reasoning, there are
problems such as Eating Grapes, Growing Worms, Common Cents, Pocket Change,
and Sharing Birthdays, all of which develop algebraic thinking.
I hope this is helpful. Please write again if you have more questions.
-Claire, for the T2T service